Electrical Fuel injection System

The electronic fuel injection system collects information by various sensors, and the computer controls the operation of fuel injectors based on the information. The EFI(Electronic Fuel Injection) system can be divided into three basic subsystems. These are the fuel delivery system, air induction system, and the electronic control system.

There are different types of gasoline fuel injection systems used in automobiles. The two basic arrangements in EFI systems are the throttle body fuel injection and the port fuel injection.

The TBI(Throttle Body Fuel Injection) is also called single point fuel injection —SPI system. Fuel is injected into the area around the throttle valve, where air velocity is at a maximum, thus ensuring fuel droplets are thoroughly atomized and will be distributed throughout the air mass.

The PFI(Port Fuel Injection, also called multi-point fuel injection—MPI64 ) system uses a solenoid fuel injection with a coil and a spring to open and close the needle valve in each cylinder. Gasoline is injected into the intake manifold above the intake valve 70-100 mm.

Safty Tips

(1) Before overhauling the fuel system components, the pressure of the fuel system must be relieved first.

(2) Safe use of air hoses: Improper use of air nozzles can cause blindness or deafness. The compressed air pressure to the air nozzles must be reduced to below 206 kPa. If using the air nozzle to dry or clean parts, do not direct the airflow at people around you. The air hose should be rolled up and placed properly when not in use.